1. Field of the Invention
The present invention relates to an apparatus for performing various surface processing and a method of the surface processing, and in particular to an apparatus wherein predetermined radiation and/or an active species, are produced, are utilized so as to fabricate insulator films of semiconductor devices, semiconductor films, metal films, and to perform surface processing of etching, surface-cleaning, and surface reforming.
2. Description of Prior Art
An advanced progress is made recently in such a surface processing that a gas is activated by way of photochemical reaction, substance to be aimed is deposited on a substrate surface to form a thin film, the etching and surface reforming are performed. This is because the surface processing can be done at low temperatures, no damage caused by bombardment of charged particle occurs, novel processing can be employed due to the selectivity of photochemical reaction, and a selection of reaction steps and film forming control can be easily achieved.
The conventional methods for the photochemical surface processing are mainly classified into two categories: One method employs a discharge lamp as a light source. The other employs a laser. The former method has a drawback that, in general, intensity of radiation of the discharge lamp is low. The later has such a drawback that the cost of the laser assembly is very high.
In the typical processing apparatus, the light source is separated from the processing chamber by the window. In particular, contamination is deposited on this window in the photo assisted chemical vapor deposition or the like, resulting in attenuation of the radiation in this area.
In the conventional processing apparatus, there are various drawbacks such that the structure is complex, limitations exist in the kinds of the surface processing, and the film forming rate is inherently low.
Generally speaking, an active species, may be produced by irradiating light or electrons or the like to a substance. The activated condition by the light is limited to either the activated condition where the light transition is not prohibited, or the activated condition produced by the intersystem crossing or relaxation from the aforementioned activated condition. To the contrary, there is no such a limitation in the other activated condition which is produced by particle bombardments inside plasma, or electrons. That is, the transition can easily extend into the activated condition where the light transition is prohibited. As a result, the active species containing various kinds of harmful impurities are produced, which is completely different from the light activated condition.
Most prior art techniques for forming films by plasma have the following drawbacks. Since plasma is directly in contact with the substrate, it is damaged by bombardment by the harmful active species or the charged particle in plasma, causing the impurities to be injected into the substrate. Accordingly, electronic characteristics of semiconductor devices fabricated on this substrate are deteriorated. Such a deterioration of the electronic characteristics is emphasized in, for instance, variations in Vth of MOS type semiconductor devices and those in hfe of bipolar semiconductor devices. A degrees of integration of semiconductor devices tends to increase in the latest technology. Consequently, since even small bombardment of charged particle causes the electronic characteristics of such semiconductor devices to be deteriorated, there is a growing need to develop non-damage surface processing by employing the impurity-less active species and the non-bombardment light.
An object of the present invention is to provide a novel surface processing apparatus and a novel processing method wherein the highly pure, strong and useful radiation as well as the active species are produced in a stable condition, whereby the high-quality surface processing can be achieved in an industrially available processing rate.